Stereoscopic viewers have enjoyed a long history of popularity among a variety of users. Understandably, a great number of stereoscopic viewer designs have been provided. However, all such stereoscopic viewers generally include a housing supporting a pair of spaced apart eyepiece lenses having optical characteristics which focus the user's eyes upon an image plane spaced from the housing. A light emitting aperture is typically provided between the eyepiece lenses and the image plane to provide a source of light for illuminating a picture or other image forming element supported upon the image plane. The viewing of the image through the spaced apart eyepieces provides a stereoscopic or "three-dimensional like" image character. While such stereoscopic viewers are enjoyable, they are typically large and somewhat bulky raising difficulties in storing and transporting the viewers. In addition, the prohibitive size and awkward shape of such stereoscopic viewers often makes them difficult to handle.
In attempting to meet the problems of awkward shape and bulky size of stereoscopic viewers, practitioners in the art have endeavored to provide various folding or collapsible viewers. Such collapsible viewers have in some respects provided improvement in the art. However, they have also typically resulted in structures which are unnecessarily costly and in many instances difficult or cumbersome to assemble or disassemble tending to make such designs unappealing to consumers.
Examples of such prior art stereoscopic viewers have been found in the patent art for many years. For example, U.S. Pat. No. 1,543,188 issued to Poser sets forth a STEREOCAMPIMETER having a support base and vertically extending pedestal upon which a stereo viewer is supported. The stereo viewer includes a pair of optical lens systems and a surrounding hood for the user's forehead. The base further supports a horizontally extending telescoping arm from which a generally planar image support plane is raised. The telescoping arm permits focal length adjustment of the image plane to eyepiece lens distance.
U.S. Pat. No. 858,979 issued to Hammar sets forth an OPTICAL INSTRUMENT having a support base upon which a pair of pivotally supported eyepiece lenses are secured. An image plane is further supported upon the base and positioned in alignment with the pivotally supported eyepieces.
U.S. Pat. No. 3,502,390 issued to Gilmore, Jr. sets forth a DENTAL STEREOSCOPE having an elongated generally rectangular box supporting an image plane at one end and a compound lens eyepiece assembly inset within the opposite end of the box. A center wall separates the optical paths of each eyepiece to the images.
U.S. Pat. No. 2,093,520 issued to Hayashi sets forth a STEREOSCOPE having a pair of trapezoidal prismatic housings commonly coupled to a frame support. The smaller end of the trapezoidal housing support eyepiece lenses while the larger ends support a film strip retainer upon which a transparency is applied. Ambient light from behind the film strips passes through the film strips to the eyepiece.
U.S. Pat. No. 2,083,313 issued to Cardoza sets forth a STEREOSCOPE having a dual eyepiece supporting housing further including a film plane support and an internal battery-powered illumination system.
U.S. Pat. No. 4,726,653 issued to Thaler, et al. sets forth a STEREOSCOPIC VIEWER having a housing supporting an advancing and supporting mechanism for a disk-shaped card carrying a plurality of stereo images. A pair of eyepieces view the pairs of stereo images.
U.S. Pat. No. 4,235,514 issued to Carver sets forth a COLLAPSIBLE STEREOSCOPIC VIEWER AND FILMSTRIP THEREFOR having a generally rectangular stereoscopic viewer supporting a pair of spaced apart lenses and eyepieces and having means for receiving Lo an elongated dual image card which supports a plurality of image pairs movable to and from positions of alignment with the viewer eyepieces.
U.S. Pat. No. 5,017,952 issued to Wheeler sets forth a COMBINATION CAMERA TO PRODUCE MULTIPLE PRINTS AND PRINT VIEWING DEVICE having a housing defining multiple light paths therein together with a film receiving zone, a print receiving zone, a viewing channel and mirror means within the housing to reflect light from an object to pass via one of the light paths to the film at the film receiving zone for exposing film and to reflect light from an illuminated print at the print receiving zone.
While the foregoing described prior art devices have provided improvement in the art and have enjoyed some commercial success, there remains nonetheless a continuing need in the art for evermore improved low cost, convenient to use and effective stereoscopic viewers.